Rotary driving mechanism



Oct. 10,1967 c Q BOTTQMS ROTARY DRIVING MECHANISM Filed Aug 20, 1965 2Sheets-Sheet 1 INVENTOR. Bov- TOMS ATTOIZNEY 0C5; 10,1967 c. c. BOTTOMS3,345,832

ROTARY DRIVING MECHAN I SM Filed Aug. 20, 1965 2 Sheets Sheet 2 Cup-F020C. BOTTQMS I INVENTOR.

A -roc'zway the outer barrel to the bumper sub while United StatesPatent 3,345,832 ROTARY DRIVING MECHANISM Clifford C. Bottoms, 403Orange Grove, San Fernando, Calif. 91340 Filed Aug. 20, 1965, Ser. No.481,261

- 7 Claims. (Cl. 6423) This invention pertains to a mechanism fordriving one shaft by another, and particularly to such a mechanismadapted for use in a drilling tool, such as an oil well drill or thelike.

In the art of deep well drilling, a hollow tubular structure, designatedthe outer barrel, is inserted in the well bore and is used to supplyrotary driving force to the drilling bit. The drilling bit is attachedto a mandrel-like member which is called a driver sub.

In one kind of welltool, the driver sub is connected to anothermandrel-like member which is called an upper sub. The connected subs aredesignated an inner barrel. The inner barrel is adapted to slide ortranslate axially relative to the outer barrel, and means are providedto transmit torque from the outer to the inner barrel. Spring shouldersare formed on the inner surface of the outer barrel and the outersurface of the inner barrel. A spring, usually a coiled spring, ispositioned between the shoulders, usually surrounding the inner barrel,to bias or force the inner barrel into its axially extended positionrelative to the outer barrel and to force the drilling bit intoengagement with the rock. As the drilling progresses, drilling mud isforced downwardly through an axial bore in the inner barrel, throughnozzles adjacent the bit into the well bore, where it serves tolubricate the bit and the outer barrel. Any tendency for the bit andinner barrel to oscillate is reduced by the spring and to some extent,by the damping effect of the drilling mud. Such a spring biased sub iscalled a percussion sub.

In a second kind of well tool, the driver sub is weighted by heavyweights to cause the drilling bit to remain in contact with the rock.The driver sub and the weights are connected to an extended mandrel-likeupper member, called a bumper sub, which is an inner barrel, enclosed inthe cylindrical outer barrel driving member. Means are provided totransmit torque from allowing relative axial translation therebetween;

The travel between the inner and outer barrels in the percussion subtype of tool may be on the order of one foot or less. In the bumper sub'type of tool, the travel between the outer barrel and the bumper sub maybe on the order of five feet or more, thus allowing the outer bar-rel tobe carried by a ship which is rising and falling. In both kinds oftools, stops are used to prevent excessive translation between the outerand inner barrels.

In prior art devices the various engagement means employed between theinner and outer barrels to transmit torque between the barrels, weresubject to excessive friction which opposed the free or spring-inducedrelative axial translation between the barrels. It was not unusual torequire tens of tons of axial force to cause the required translation.Due to the excessive friction, the engaging surfaces would wear, causingrotational play between the barrels and reducing the life of the tool.Further, because of the need to use great weights with these bumpersubs, the moment of inertia of the weights increased the amount oftorque necessary to rotate the inner barrel, weights and driver sub, andthe impaired.

The device of this invention uses rolling means between the inner andouter barrels to transmit torque while allowing relative axialtranslation. As one result, the friction is substantially reduced. Forexample, where perhaps twenty tons of axial force might be requiredbefore this invention, now only about 1,000 pounds of axial force mayfurnish the equivalent drilling effect.

In one embodiment of the device of this invention, a plurality ofaxially directed channels are formed, by

machining or other convenient methods, on the inner surface of the outerbarrel. The channels are distributed at spaced intervals about thecircumference of the barrel. A like number of channels are formed on theouter surface of the inner barrel to register with the channels on theinner surface of the outer barrel. With the inner barrel inserted in theouter barrel and the channels in registry, a plurality of hardened steelballs are placed in each of the axial races formed thereby so that eachball rolls freely between the two barrels. The balls thus carry torquefrom the outer to the inner barrel. Preferably the channels arecontoured to the balls to allow them to roll with a maximum of wear onthe contact surfaces.

In a second embodiment of the invention, the barrels are adapted toreceive a plurality of axles directed radially inwardly from the innersurface of the outer barrel or alternatively, outwardly from the outersurface of the inner barrel. The latter arrangement is preferable forease of assembly. The axles are arranged in spaced axially aligned rows.On the adjacent surface of the other barrel, in register'with theserows, are a plurality of axially oriented channels adapted to receiverolling members, such as rollers. A roller is attached to each axle androlls in one of the channels. The contour of the channel is adapted tomatch the shape of the rollers.

The rollers may be mounted on bearings to rotate relative to the axlesor, alternatively, may be fixed to the axles with the axles mounted inbearings relative to their supporting barrel.

The rollers may be of various shapes, as for example, cylindrical,conical or spherical.

Further, although it may be desirable that all of the channels beaxially aligned, it is not necessary, and they may be staggered alongthe barrel.

A permanent lubricant, such as oil, surrounds the rolling members and isretained by means of packings placed near the ends of the channels.These packings also function to keep dirt out of the rolling means. In apercussion sub, the lubricant may also surround the spring as well asall of the internal moving parts.

It is an object of this invention to reduce the friction between aninner and outer barrel of a well tool.

It is another object of this invention to provide means for eflicientlytransmitting torque between well tool barrels having greatly reducedfrictional resistance to relative axial translation.

It is still another object to use rolling means having one degree offreedom of motion while transmitting torque between two shafts.

A further object of this invention is to provide a very durable, easilymanufactured means to transmit torque between two substantially coaxialshafts while all-owing axial translation therebetween.

It is a specific object of this invention to provide apparatus which isadapted to achieve the above enumerated objects.

Other objects will become apparent from the following description, takenin connection with the accompanying drawings in which:

FIGURE 1 is a side elevational view, partly in profile and partly insection, with several portions cut away showing a well tool embodyingthis invention employing a percussion sub, with the sub in its extendedposition;

FIGURE 2 is a similar view of the device of FIGURE 1, with the sub shownin its retracted position;

FIGURE 3 is a similar view, partly in profile and partly in section, ofa well tool of this invention employing a bumper sub;

FIGURE '4 is an exaggerated view, partly in section, taken at a positioncorresponding to 44 in FIGURE 2 and showing a fanciful array of severalalternative forms of channels adapted to receiving the rolling means ofthe invention; and

FIGURE 5 is a similar exaggerated view, partly in section, taken at aposition corresponding to 44 in FIG- URE 2, showing several otheralternative embodiments of rolling means, their attachment means, andtheir associated receiving channels.

Wherever possible like numerals are used in the drawings to designatelike parts.

In the well tool of FIGURES 1 and 2, an outer barrel drives a percussionsub 12, forming a portion of an inner barrel 14. The percussion sub 12is connected to drive a driver sub 16 which drives the bit 18. The innerbarrel 14, comprising the percussion sub 12 and the driver sub 16, isbiased toward an extended position by a coil spring 20 which seatsbetween a shoulder 21 on the inner surface of the outer barrel 10 and ashoulder 23 on the outer surface of the inner barrel 14. The length oftravel is between stop 22 in the extended position of FIGURE 1 and stop24 in the retracted position of FIGURE 2.

In the well tool of FIGURE 3, an outer barrel 10 drives a bumper sub 26which is attached to drive a driver sub 16 and a bit 18. Connected abovethe driver sub 16 is a plurality of weights, called collars, one ofwhich is shown at 28. These weights aid in keeping the bit 18 in contactwith the rock during the actual drilling operation.

The travel of a typical bumper sub 26 relative to the outer barrel 10 ison the order of five feet; however, this may be substantially increasedwhere, as in drilling operations at sea, the drilling rig is rising andfalling and it is necessary to compensate for this movement in order tokeep the drill at the bottom of the hole.

In the well tool of FIGURES 1 and 2, the inner barrel, comprising thepercussion sub and driver sub, are driven by the same mechanism as theinner barrel comprising the bumper sub 26 of FIGURE 3. I

In the drawings the channels are depicted as being uniformlycircumferentially distributed. This is a preferred embodiment but is notabsolutely necessary. Further, although the channels 30 and 33 are shownextending axially the same distance, and are axially positioned in thesame region, the channels may be axially staggered (not shown) ifdesired.

A plurality of circumferentially disposed substantially axial alignedchannels is formed on the inner surface of the outer barrel 10. Thesechannels may take a number of shapes, such as those illustrated inFIGURE 4, and designated by numerals 3t), 31, 32, 33,34 and 35.Generally in practice all of the channels in a given barrel will beidentical, whether rectangular in cross section, as channels 30 and 33,or of one of the other sectional forms shown or suggested.

On the outer surface of the inner barrel 14 a plurality of substantiallyaxially directed channels, equal in numher and in register with thechannels on the outer barrel is formed. Typical channels 38, 39, 40, 41,42 and 43 are shown in the section view of FIGURE 4, in register withthe channels 30, 31, 32, 33, 34 and 35 on the outer barrel. Althoughchannels 41 and 42 are shown rectangular in section, while the remainingchannels are circular in section, in a preferred embodiment of theinvention all of the channels on the inner barrel will have the sameshape and will be identical with those on the outer barrel. The twoshapes are shown by way of example only. The structures formed byregistering pairs of channels in the two barrels effectively form aplurality of keyways, and constitute an essential part of the subjectinvention.

A plurality of rolling means, such as steel balls, shown generally at 50and 52 in FIGURES 1, 2 and 3 are inserted in the keyways formed byadjacent pairs of channels in the inner and outer barrels. A typical setof such balls are also shown in FIGURE 4 at 5'3, 54, 55 56, 57 and 58.

As an alternative form of rolling means, a plurality of radially outwardextending axles may be attached to the outer surface of the inner barrel14. These axles are preferably aligned in axially directed rows. Therows are circumferentially distributed about the coincident centrallongitudinal axes of the barrels. On each of the axles is a roller. Aplurality of axially directed channels are formed in the inner surfaceof the outer barrel to receive the rollers.

FIGURE 5 is offered to show several different embed} ments of theserollers and to show a few of the possible cross-sectional forms thechannels may take. The size of the rollers and channels relative to thedimensions of the inner and outer barrels has been exaggerated. Further,it is to be stressed that the axles are shown attached to the innerbarrel with the channels in the outer barrel only for convenience ofassembly. Although not so illustrated in the drawings, it is within thescope of this invention to attach the axles to the outer barrel, and toform the receiving channels in the inner barrel.

Referring to FIGURE 5, a plurality of axles 70, 71, 72, 73, 74 and 75are shown attached to the inner barrel 14. The axles 71 and 72 are shownmounted for rotation, relative to barrel 14, upon bearings 76 and 77.The remaining axles are shown screwed into the inner barrel 14. Thedifferent embodiments are by way of example only. Mounted upon the axlesare rolling means such as rollers 80, 81, 82, 83, 84 and 85. Each of therollers 81, 82 and 83 is shown as cylindrical in shape. Roller is shownas spherical, roller 84 is shown as a truncated diverging cone, androller 85 is shown as a truncated converging cone. These five shapes arenot intended to be exhaustive of the forms the rolling means may take,but are representative examples only. In a preferred embodiment all ofthe rollers would be substantially identical. The channels 90, 91, 92,93, 94 and 95 are axially aligned in register with rows of the rollersand are contoured to conform to their associated rollers. Notice thatfor a rotation direction indicated by arrow 100, the channels arecontoured to cause the rollers to contact the channel sides, for exampleat 102, to carry torque from barrel 10 to barrel 14. Clearance isprovided, as for example at 104, to prevent the rollers from rubbingexcessively against the sides of the channels. Notice that when theaxles, such as axles 71 and 72, are mounted for rotation upon bearings,such as bearings 76 and 77, relative to the inner barrel 14, the rollers81 and 82 are usually firmly attached to theaxles. When the axles, suchas axles 70, 7.3-, 74 and 75 are firmly attached to barrel 14, theirassociated rollers 80, 83, 84 and 85 are mounted upon bearings (notshown) for free rotation relative to their supporting axles.

To protect the moving parts of the rolling means in all of theembodiments of this invention, it is desirable to lubricate the balls,rollers, and bearings. To that end, a

lubricant, such as oil, is inserted into the spaces surrounding themoving parts. In a well tool using a percussion sub, it is frequentlyalso desirable to lubricate the spring 20. To prevent the lubricant fromleaking out and to prevent dirt and drilling mud from leaking in,typical packings such as those shown at 120 and 122 are used.

In combination the keyways formed by the channels on the inner or outerbarrel or by registering pairs of channels in both barrels and therolling means associated with them form a structure which serves as anextremely eflicient, new and novel torque transmitting spline which isadaptable to a great variety of uses.

In operation, the outer barrel is rotated by means (not shown) locatedin the drilling rig above ground. The rolling means, such as the balls50, 52, 53, 54, 55, 56, 57 and 58 of FIGURES 1-4, or those denoted bynumerals 80, 81, 82, 83, 84 and 85 of FIGURE 5, transmit torque from theouter barrel 10 to the inner barrel 14 while allowing great freedom ofaxial translation between the barrels. It is to be stressed thatalthough the invention is described as carrying torque from the outer tothe inner barrel, that the device of this invention could just as easilycarry torque from the inner barrel to the outer barrel while allowingnearly frictionless relative axial translation between the barrels.

Although the invention has been described in detail above, it is notintended that the invention should be limited by that description, butonly in accordance with the spirit and scope of the following claims.

What is claimed is:

1. A well tool having a percussion sub comprising:

an outer barrel, adapted to be rotated, having a plurality ofcircumferentially distributed substantially axial channels positioned ina region of the inner surface thereof, adapted to receive rolling means;

an inner barrel, including a percussion sub and a driver sub, having aplurality of substantially axial channels, equal in number to the abovesaid channels and in register with the above said channels, upon theouter surface of a portion of said inner barrel;

a plurality of rollings means, positioned in said two sets of channelsto transmit torque from said outer barrel to said inner barrel to rotatesaid inner barrel while allowing relative axial translation between saidbarrels;

shoulders on the inner surface of said outer barrel and the outersurface of said inner barrel;

resilient means positioned between said shoulders to bias said innerbarrel toward its extended position;

a lubricant surrounding said rolling means; and

means for retaining said lubricant.

2. A device as recited in claim 1 in which said rolling members areballs, and said channels are contoured to receive said balls.

3. A well tool having a percussion sub comprising:

an outer barrel, adapted to be rotated, having a plurality ofcircumferentially distributed substantially axial channels positioned ina region of the inner surface thereof, adapted and contoured to receiverollers;

an inner barrel, including a percussion sub and a driver sub, having aplurality of radially directed axles extending from the outer surfacethereof, arranged in a plurality of substantially axial rows in registerwith said channels;

a plurality of rollers, equal in number to said axles, attached to rollabout the axes of said axles and positioned to engage and roll in saidchannels to carry torque from said outer to said inner barrel whileallowing relative axial translation;

shoulders on the inner surface of said outer barrel and the outersurface of said inner barrel;

a spring positioned between said shoulders to bias said inner barreltoward its extended position;

6 a lubricant surrounding at least said rollers; and means for retainingsaid lubricant.

4. A device as recited in claim 3 in which said lubricant also surroundssaid spring and further comprising stops for limiting the relativetranslation between said barrels.

5. A well tool having a bumper sub comprising:

an outer barrel, adapted to be rotated, having a plurality ofcircumferentially distributed substantially axial channels positioned ina region of the inner surface thereof, adapted and contoured to receiverollers;

an inner barrel, including a bumper sub, having a plurality of radiallydirected axles extending from the outer surface thereof, arranged in aplurality of substantially axial rows in register with said channels;

a plurality of rollers, equal in number to said axles,

attached to roll about the axes of said axles and positioned to engageand roll in said channels to carry torque from said outer barrel to saidbumper sub while allowing relative axial translation;

a lubricant surrounding said rollers; and

means for retaining said lubricant.

6. A well tool having a percussion sub comprising:

an outer barrel, adapted to be rotated, having a plurality ofcircumferentially distributed axially directed channels along its innersurface adapted to receive a plurality of rolling members;

an inner barrel, including a percussion sub and a driver sub, adapted toreciprocate within said outer barrel between a closed position definedby a first pair of opposed shoulders on said outer barrel and innerbarrel and an extended position defined by a second pair of shouldersprovided on the inner surface of said outer barrel and the outer surfaceof said inner barrel;

a plurality of circumferentially distributed axially aligned channels inthe outer surface of said inner barrel registering with the aforesaidchannels in said outer barrel and adapted to receive said rollingmembers;

a plurality of rolling members positioned to engage and roll in saidchannels to carry torque from said outer barrel to said inner barrelWhile allowing relative axial translation of said barrels between saidclosed position and said extended position;

a third pair of opposed shoulders on the inner surface of said outerbarrel and the outer surface of said inner barrel;

a spring positioned between said third pair of shoulders to bias saidinner barrel toward said extended position;

a lubricant surrounding said rolling members; and

means for retaining said lubricant.

7. A well tool comprising:

an inner barrel including a percussion sub and a driver sub having aplurality of radially directed axles extending from the outer surfacethereof arranged in substantially axial rows, said rows beingcircumferentially distributed about the axis of said barrel;

a plurality of rolling means attached to roll about the axes of saidaxles;

an outer barrel having a plurality of channels formed in the innersurface thereof in register with said rolling means and contoured toengage the surfaces thereof;

said rolling means positioned in said channels to carry torque bet-weensaid barrels while allowing relative' axial translation;

shoulders on the inner surface of said outer barrel and the outersurface of said inner barrel;

spring means positioned between said shoulders to bias said inner barreltoward an extended position;

stops on said inner and outer barrels to limit the axial travel thereof;

7 8 a lubricant surrounding said rolling means; and 2,774,568 12/1956Jones 64-23 X means for retaining said lubricant. 2,943,603 7/ 1960Bassinger.

2,972,471 2/1961 McClintock 175293 References Cited 2,996,131 8/ 1961Greenwood 175293 5 3,001,387 9/1961 Schultz 64-23 UNITED STATES PATENTS3,203,202 8/1965 Brownyer 64-23 5/1903 Lehman 64-23 3 1907 Yost 4 23FOREIGN PATENTS 2/1928 BfaSWell 3 23,434 7/1913 Norway. 4/1938 Heaston64-23 X 2/ 1940 Coates 173-97 10 HALL C. COE, Primary Examiner. 5/ 1942Greiner 64-23

1. A WELL TOOL HAVING A PERCUSSION SUB COMPRISING: AN OUTER BARREL,ADAPTED TO BE ROTATED, HAVING A PLURALITY OF CIRCUMFERENTIALLYDISTRIBUTED SUBSTANTIALLY AXIAL CHANNELS POSITIONED IN A REGION OF THEINNER SURFACE THEREOF, ADAPTED TO RECEIVE ROLLING MEANS; AN INNERBARREL, INCLUDING A PERCUSSION SUB AND A DRIVER SUB, HAVING A PLURALITYOF SUBSTANTIALLY AXIAL CHANNELS, EQUAL IN NUMBER TO THE ABOVE SAIDCHANNELS AND IN REGISTER WITH THE ABOVE SAID CHANNELS, UPON THE OUTERSURFACE OF A PORTION OF SAID INNER BARREL; A PLURALITY OF ROLLINGSMEANS, POSITIONED IN SAID TWO SETS OF CHANNELS TO TRANSMIT TORQUE FROMSAID OUTER BARREL TO SAID INNER BARREL TO ROTATE SAID INNER BARREL WHILEALLOWING RELATIVE AXIAL TRANSLATION BETWEEN SAID BARRELS;